WebRTC should always be gated behind permissions. Most uses are video/audio, which already require a prompt, so no problem. Other websites shouldn't have this capability, so annoying users is no problem. But that's not very palatable, as it means acknowledging that WebRTC data doesn't really belong on the wider web.
Honestly, what are the real good uses for it outside of media? Games? WebTorrent?
I'm rather annoyed that such a feature was deployed, giving any webpage the ability to override my proxy settings or otherwise change the normal browser networking behaviour.